Keyboard



FIG. 1 is a front, top and side perspective view of a keyboard showing my new design;

FIG. 2 is a left side elevational view thereof on an enlarged scale;

FIG. 3 is a right side elevational view thereof on an enlarged scale;

FIG. 4 is a rear elevational view thereof on an enlarged scale. 

The ornamental design for a keyboard, substantially as shown and described. 